Key Points of Tobacco Cultivation Techniques and Field Management Methods Explained

First, before germinating, tobacco seeds should be placed in sunlight at 15—20°C for 2—3 days; second, the best transplanting period in the Huang-Huai tobacco region should be completed from Qingming to before Guyu. The planting density should be controlled at 1200—1300 plants per mu, and plastic film mulching should be used for planting tobacco. Third, the signs of tobacco leaf maturity are: the leaves change from green to yellow-green, the fine hairs on the leaf surface fall off, and the angle between stem and leaf increases (approximately 90 degrees). The upper, middle, and lower leaves can be harvested and flue-cured only after the main veins turn white.

1. Seedling raising: Before germinating, tobacco seeds should be placed in sunlight at 15—20°C for 2—3 days to increase the germination vigor and germination rate of the seeds. To cultivate strong seedlings, first, adopt the new double-layer film paper tube seedling-raising technique; the paper tube diameter should be no less than 4 cm, the height should be 6—7 cm, with 625 seedlings per sq m; a 10 sq m seedling bed of 1 strip can supply 4 mu of tobacco field for planting. Second, prepare nutrient soil, using 60% field soil and 40% decomposed pigpen manure as the substrate; each strip requires about 0.8—1 cubic meter of nutrient soil, and after disinfection, mix in 3—4 kg of compound fertilizer. Third, sow early at the right time and transplant early, which can increase yield by 20% and improve quality by 25%. In the Huang-Huai tobacco region, sowing should be done around the beginning of spring to mid-February. Fourth, seedling bed management: because the temperature is relatively low at sowing time and the seedlings are prone to low-temperature damage, timely regulation should be carried out according to the temperature and humidity requirements for tobacco seedling growth. Generally, thinning is carried out twice; the first time after the “cross stage”, with a seedling spacing of 1.5—2 cm, and the second thinning (final spacing) when there are 4—5 true leaves, with a seedling spacing of 6—8 cm.

2. Transplanting: Timely early planting is a key part of producing high-quality tobacco. The best transplanting period in the Huang-Huai tobacco region should be completed from Qingming to before Guyu. The planting density should be controlled at 1200—1300 plants per mu. Using plastic film mulching to plant tobacco can not only increase temperature and preserve moisture, but also improve the drought resistance and waterlogging resistance of the tobacco plants, and can prevent tobacco leaves from turning black and scorching. If there is thorough rain before transplanting, the film can be covered in time after the rain to preserve soil moisture and raise temperature. If there is no rain, sufficient bottom water should be provided when planting tobacco, and after planting the plastic film should be covered tightly (if planting tobacco around Qingming, because the temperature is relatively low, the film can be covered first and the seedlings exposed later; when the temperature stabilizes, cut open the plastic film, take out the tobacco seedlings, and seal the opening at the roots by pressing the film to prevent water loss).

3. Field management: The most prominent problem in flue-cured tobacco production is the contradiction between yield and quality. Generally, the higher the yield, the worse the quality, but it is not that the lower the yield, the better the quality. Therefore, management should focus on stabilizing yield and ensuring quality. ① Apply fertilizer in appropriate amounts: mainly base fertilizer, using the new balanced fertilization technique. Before transplanting, the amount of pure nitrogen fertilizer applied per mu should be 6 kg for low-fertility fields, 5 kg for medium-fertility fields, and 3—4 kg for high-fertility fields; the ratio of nitrogen, phosphorus, and potassium fertilizer should preferably be 1:2:3. If fertilizer deficiency is found in the middle and late stages, topdress by foliar spraying. ② Timely irrigation and drainage: during the key water-demand period of tobacco, if the tobacco field is dry, spraying irrigation 1—2 times can increase yield by 8.1—43.1% and improve quality. If the tobacco field is waterlogged for 1—2 days, yield will decrease by 47.8—65%. Low-lying tobacco fields or rainy seasons should be drained by clearing ditches. ③ Pay attention to intertillage and hilling: under dry conditions, timely intertillage is of great significance for preserving soil moisture and storing water. Timely intertillage after rain can reduce soil moisture, increase soil permeability, raise soil temperature, and promote root growth. Intertillage can also eliminate weeds and reduce diseases and insect pests. Timely hilling combined with intertillage can promote new roots, expand the ability to absorb water and fertilizer, help drainage and prevent waterlogging, and enhance drought resistance and wind resistance against lodging. ④ Timely topping and removal of branches: topping and removal of branches can not only increase yield by 31—49%, but is also the main way to improve tobacco quality. Topping should generally be completed in two operations according to the number of leaves retained, to promote uniform tobacco plants and uniform yellowing during growth, which is beneficial for flue-curing. Plant branches should be removed promptly and cleanly. ⑤ Strengthen pest and disease control: focus on prevention, combining chemical control and manual capture.

4. Harvesting: Mature harvesting is one of the important links in high-quality tobacco production. The signs of tobacco leaf maturity are: the leaves change from green to yellow-green, the fine hairs on the leaf surface fall off, and the angle between stem and leaf increases (approximately 90 degrees). The lower leaves can be harvested and flue-cured only after the main veins turn white, the middle leaves after the branch veins turn white, and the upper leaves after the main and branch veins turn white and yellow spots appear on the leaf surface.